World Legendary Powders

After playing this game for a while, I realized many similarities with this game and Diablo 3. One thing I think we can incorporate into this game to allow for a better and less boring end game would be upgradable legendary powders.

Go into detail. -
Alright, so we all know that the end game currently is incredibly boring. What if we added a new legendary system for powders? Similarly to Diablo 3, we can have these upgradable powders that not necessarily increase damage, but do things such as +mana regen, +life steal, +hp regen, +move speed, etc. However, we would cap their level at 10. Also, they can be upgraded at a new merchant.
For example,
Ashes of the Awakened
[Tier 1 *---------]
Effects on Weapon:
+2% Spell Damage

Effects on Armor:
+2% Reflection

And this would scale +2% SD and +2% Reflection for every level, capping at +20% Spell Damage and +20% Reflection. (Sorry if these numbers are a little bit insane/underwhelming, I don't know much about late game builds)

Is it possible? -
I believe yes, for unused dungeons such as the Corrupted Ice Barrows, Corrupted Underworld Ruins, and Corrupted Galleon's Graveyard, instead of the reward being just bland loot, make them reward one legendary powder + stuff used for powder upgrades + the normal loot. However, since we don't want people to just spam Corrupted Ice Barrows to get their legendary powders, make the more difficult dungeon give more powder upgrade items than the easier ones.
For example, a new NPC outside the 3 unadded corrupted dungeons would be able to upgrade your powder, however you would need to pay the necessary amount of the powder upgrade item to successfully upgrade it.

Does it fit?
Yes

Has it been suggested before?
Don't think so.

Have any questions? I'll answer them in the comments,

 

Tone down the numbers.
50% spell damage is literally insane.
Don't even get me started on reflection, can you imagine poison cactus with this?

 

Sorry, don't know how stats should scale, haven't really reached the end game yet.

 

make it a 1% per upgrade. So at level 10 it'll be 10% id. It's not bad, and not too op.
Add moar detail. Dungeons should not be the way to grind legendary powders. What other legendary powders are there? Lore? Where can this merchant be found?

 

wow wish i had some